I've only been able to find one other person who adds Pfertz and Excel to their spray bottle while doing a dry start method. I added a few drops of n, p , k, and excel to my spray bottle. Is this enough/not enough? And would it be beneficial, not necessary, or even hurt my plants?

Substrate: Aquasoil Amazonia NEW (normal/powder)
Plants: HC and DHG

I appreciate any input.

With a dry start the plants are getting their nutrients through the roots only. Amazonia has more than enough nutrients by itself to do dry starts, so I don't see a reason for adding anything to the spray bottle.

would it do any harm by using ferts?

Excel is liquid carbon, your plants are pulling enough CO2 out of the air to be very happy. Not sure about the fertz but your using new amazonia so you shouldn't need it. I guess at the EXTREME end of spraying your plants with fertilizer is having it collect on the leaves and causing some burning.